Pulmonary Tumor Thrombotic Microangiopathy (PTTM) Caused by Metastatic Ovarian High-Grade Serous Carcinoma: A Rare Case Report and Literature Review

Abstract

Abstract Introduction/Objective Pulmonary tumor thrombotic microangiopathy (PTTM) is a rare entity, and often diagnosed in postmortem. PTTM is usually presented as unexplained dyspnea in a patient with known or unknown history of cancer. Tumor microemboli mainly affect the pulmonary microvasculature. PTTM is resulting from coagulation cascade activation secondary to tumor microemboli induced fibrin clot formation and fibrocellular intimal proliferation. Methods/Case Report The patient is a 65-year-old female with past medical history of ovarian high-grade serous carcinoma, and presented to the hospital with chest pain and shortness of breath. Coronary angiography showed no new obstructive disease. Echocardiogram revealed markedly elevated right ventricular systolic pressure (65-70 mmHg), indicated pulmonary hypertension. Computed tomography of the chest revealed diffuse bilateral ground glass and solid centrilobular nodules, with no pulmonary emboli identified. She developed worsening hypoxia and expired. A lung-restricted autopsy was performed. Literature review was conducted. The important gross findings included multiple firm and red-brown nodules (approximately 0.1 cm) in bilateral lungs. Microscopic examination revealed the lung parenchyma demonstrated numerous tumor microemboli in the pulmonary arterioles and occasionally in the small arteries. The tumor microemboli consist of tumor cells with various degree of fibrin deposition and fibrocellular intimal proliferation. The tumor cells were epithelioid with moderate to marked nuclear pleomorphism, occasional cytoplasmic vacuoles, frequent apoptosis and necrosis. Immunohistochemical stains for PAX-8 and WT1 highlight the tumor microemboli. These findings are consistent with PTTM secondary to metastatic ovarian high-grade serous carcinoma. Rare cases of PTTM associated with ovarian cancer were found in PubMed. Results (if a Case Study enter NA) NA. Conclusion PTTM has poor prognosis. There are no sensitive diagnostic modalities, and majority of them are diagnosed at autopsy. We have found four reported PTTM cases caused by metastatic ovarian cancer in PubMed, including one case of clear cell carcinoma and three cases of low-grade serous carcinoma. Our current report of PTTM is associated with high-grade serous carcinoma, which is not seen in the literature. The awareness of PTTM is necessary for patients with ovarian cancer.